The present invention relates to a light emitting element array having a plurality of light emitting elements such as light emitting thyristors arranged therein; a drive circuit for driving the light emitting element array in a time division way; an optical print head including the light emitting element array and the drive circuit; and an image forming apparatus such as an electro-photography printer including the optical print head.
In a conventional image forming apparatus (for example, an electro-photography printer using an electro-photography process), a light emitting diode (LED) print head has a plurality of LEDs arranged in a matrix pattern (refer to Patent Reference). A power MOS transistor is connected to a common connection terminal of the LEDs, so that the LEDs to be lit are switched in a time division way.    Patent Reference: Japanese Patent Publication No. 2007-81081
In the conventional LED print head having a plurality of LEDs arranged in a matrix pattern, the number of the LEDs may reach few thousands. When all of the LEDs emit light, a large current flows through the common connection terminal. Accordingly, it is necessary to provide the power MOS transistor with a capability of driving a large current. As a result, a chip size of the power MOS transistor increases, thereby making it difficult to reduce a size of the LED print head or cost thereof.
In view of the problems described above, an object of the present invention is to provide a light emitting element array, a drive circuit, an optical print head, and an image forming apparatus capable of solving the problems of the conventional light emitting element array.
Further objects and advantages of the invention will be apparent from the following description of the invention.